1. Field of the Invention
This invention relates to a method of producing a compound by fermentation.
2. Description of Related Art
The traditional organic chemical synthesis of industrial quantities of a structurally complex natural product or an analog thereof is often inefficient because of the product's structural complexity. An alternative is biosynthesis, via the fermentation of a culture of an organism capable of producing the product. Where the product is not a natural product, a genetically modified organism may be used. In either case, the product must be isolated from the culture medium and the producing organism at the conclusion of a fermentation run. A common isolation technique is to contact the fermentation broth with a resin that adsorbs the product. The contacting may be accomplished by passing the broth through a chromatography column loaded with the resin or by adding the resin to the broth and stirring. The resin and broth are separated, after which the product is isolated by elution from the resin. As most products are hydrophobic molecules, hydrophobic (unfunctionalized) resins are preferred. See, for example, Ashley et al., U.S. Pat. No. 6,492,562 B1 (2002); Chu, U.S. Pat. No. 6,514,944 B2 (2003); Ashley et al., US 2002/0045609 A1 (2002); Santi et al., US 2002/0052028 A1 (2002); Santi et al., US 2002/0137152 A1 (2002); Ashley et al., US 2003/0023082 A1 (2003); and Ashley et al., US 2003/0096374 A1 (2003); the disclosures of which are incorporated herein by reference.
In a variation of the above technique, the resin is present during the fermentation run, either ab initio (i.e., at the time of seeding) or starting partway through it. The resin's presence has been reported to improve production levels and, where the product is unstable, to sequester it and prevent its degradation. See, for example, Ligon et al., U.S. Pat. No. 6,117,670 (2000); Peterson et al., U.S. Pat. No. 6,242,211 B1 (2001); McDaniel, U.S. Pat. No. 6,403,775 B1 (2002); Khosla et al., US 2002/0119937 A1 (2002); Khosla et al., US 2003/0077760 A1 (2003); Nasby et al., WO 98/41869 (1998); Yamazaki et al., EP 0,546,819 A1 (1993); Marshall et al., J. Ind. Microbiology 5,283-288 (1990); Jarvis et al., J. Antibiotics 43 (11), 1502-1504 (1990); Gerth et al., J. Antibiotics 47 (1), 23-31 (1994); and Warr et al., J. Antibiotics 49, 234-240 (1996); the disclosures of which are incorporated herein by reference.
A resin's presence can also control the distribution of a product mixture. For instance, in the production of epothilones by fermentation of recombinant Myxococcus host cells, epothilones A and B are produced when resin is absent but epothilones C and D are produced when resin is present. See Julien et al., U.S. Pat. No. 6,410,301 B1 (2002) and Arslanian et al., US 2003/0073205 A1 (2003); the disclosures of which are incorporated by reference.
When a patient's bodily fluid sample is cultured to identify and isolate an infecting microorganism that might be present, antibiotics previously administered to the patient can interfere with the culturing process. The addition to the culture medium of a resin to adsorb and isolate the interfering chemicals is taught in Waters et al., U.S. Pat. No. 5,624,814 (1997), the disclosure of which is incorporated herein by reference.